DE102017114570A1 - Burner head and combustion process - Google Patents

Abstract

The invention relates to the combustion of fuel in a burner head spaced, downstream combustion zone in a combustion chamber. In a burner head and a combustion method, in which a first partial volume flow of the combustion air is helically twisted, it is proposed to vortex at least a second partial volume flow of the combustion air before the two partial volume flows are mixed with each other and subsequently with unburned fuel , which increases the stability of the flame and reduces pollutant emissions.

Description

The present invention relates to the combustion of fuel in a burner head spaced, downstream combustion zone in a combustion chamber.

When fossil fuels are burned in combustion plants, environmentally harmful pollutant emissions generally arise, in particular in the form of nitrogen oxides (eg NO, NO 2), which are usually referred to collectively as NO x. In the case of nitrogen oxides, the recirculation or recirculation of exhaust gases produced during combustion has proven to be effective. Recirculated exhaust gases lead to a reduction of nitrogen oxides produced during combustion. By recirculating exhaust gas, the flame temperature and partial pressure of oxygen can be lowered, thereby reducing nitrogen oxide formation, which is caused by high combustion temperatures, and / or fuel mixtures having a stoichiometry resulting in a reduction of nitrogen oxide. However, mixing in of exhaust gas tends to destabilize the flame.

From the prior art, it is known to combust fuel in two stages, wherein fuel is burned in two different, consecutive combustion zones in the flow direction. Such an approach is for example off DE 195 09 219 A1 known.

Alternatively, one-stage burns, especially when recirculating exhaust gas, are used. For example, methods and apparatus for single-stage combustion are known EP 1 245 901 A1 . DE 197 04 721 A1 and DE 10 2005 038 662 A1 known. However, prior art approaches to single stage combustion have difficulty stabilizing a flame away from the combustion head (referred to in the art as "free flame technology") whose overcoming requires additional measures.

The above statements apply in particular to pure gas burners (single-fuel burners) and gas-oil burners (dual-fuel burners) in gas operation. For an oil burner (single fuel burner) or gas-oil burner (dual fuel burner) in oil operation, there are comparable problems with regard to the stabilization of the flame, although they are lower here. Further, here too, the mixing of fuel (e.g., oil) and combustion air is important to the resulting fuel-combustion air mixture and overall fuel performance. The more intensive and homogeneous the mixing can be achieved, the more optimal the burning process. However, the mixing of fuel (eg, oil, gas) and combustion air is an aspect to be improved.

To the problem of providing the combustion of fuels for improved training and stabilization of a spaced apart from the combustion head flame and thereby minimize the formation of pollutants, in particular nitrogen oxides, by exhaust gas recirculation, is in EP 2 037 173 B1 a burner head is proposed for one-stage combustion of fuel in a burner head downstream combustion zone comprising a burner tube with a downstream end, a swirl device for supplying twisted combustion air in a first combustion-free mixing zone downstream of the swirl device within the burner tube and at least one first fuel nozzle downstream of the swirl means and disposed within the burner tube and for supplying fuel to the first mixing zone to mix unburned fuel with combustion air twisted by the swirl means. The swirl device comprises a first region with swirl elements, with which the swirling device supplied combustion air is twisted. The swirling device furthermore has a second region, which is located downstream of the first region and is designed such that in the first region, twisted combustion air is conducted separately from further combustion air (in particular guided in the burner tube).

The term "twisted" is in EP 2 037 173 B1 so defined that "combustion air, the upstream of the swirl device 38 essentially only in the flow direction 24 (or with respect to the longitudinal axis 24 in the axial direction) has flowing portions, so with the swirl elements 46 interacts that downstream of the area 44 the flowing combustion air comprises flow components which, relative to the longitudinal axis of the burner tube 2 - extend axially, radially and tangentially. "In other words, in EP 2 037 173 B1 the term "twisted" synonymous with "helical" used.

Although by the in EP 2 037 173 B1 proposed measures compared to the cited prior art actually improvements could be achieved in the sense of the object of the invention, it has been shown that - especially due to the ever-increasing benefits of newly developed burner heads - the ever-increasing demands of current emission standards alone by these measures more difficult are reachable.

There is therefore still a need for technical solutions for burner heads and combustion processes, with which the stability of the flame improved and the pollutant emissions, in particular of carbon monoxide, nitrogen oxides and (especially in oil operation) soot can be reduced.

Based on the cited prior art, an improved burner head with the features of independent claim 1 and an improved combustion method with the features of independent claim 9 are therefore proposed.

• • ein Brennerrohr mit einem stromaufwärts gelegenen ersten Ende zum Einspeisen von Verbrennungsluft in das Brennerrohr, und einem stromabwärts gelegenen zweiten Ende zur Abgabe eines zündfähigen Gemischs aus Brennstoff und Verbrennungsluft;
• • mindestens ein in dem Brennerrohr koaxial angeordnetes Brennstoffrohr mit mindestens einer im Bereich des zweiten Endes des Brennerrohres angeordneten Brennstoffdüse, zur Zufuhr von Brennstoff in eine im Bereich des zweiten Endes des Brennerrohres angeordnete Mischzone;
• • eine in dem Brennerrohr koaxial angeordnete Dralleinrichtung mit einem Drallrohr sowie darin angeordneten Drallelementen, das einen ersten Strömungsquerschnitt aufweist, der innen durch das mindestens eine Brennstoffrohr und außen durch das Drallrohr begrenzt ist, zur Zufuhr eines ersten Teil-Volumenstroms schraubenlinienförmig verdrallter Verbrennungsluft in die stromabwärts der Dralleinrichtung angeordnete Mischzone; und
• • mindestens einen in dem Brennerrohr koaxial angeordneten zweiten Strömungsquerschnitt, der innen durch das Drallrohr oder mindestens ein das Drallrohr umschließendes Überrohr und außen durch mindestens ein das Drallrohr umschließendes Überrohr oder das Brennerrohr begrenzt ist, zur Führung mindestens eines zweiten Teil-Volumenstroms von Verbrennungsluft getrennt von dem in der Dralleinrichtung schraubenlinienförmig verdrallten ersten Teil-Volumenstrom von Verbrennungsluft in die stromabwärts der Dralleinrichtung angeordnete Mischzone.

First proposed is a burner head for combusting fuel in a combustion zone downstream of the burner head, comprising:

• A burner tube having an upstream first end for feeding combustion air into the burner tube, and a downstream second end for discharging an ignitable mixture of fuel and combustion air;
• At least one fuel tube arranged coaxially in the burner tube and having at least one fuel nozzle arranged in the region of the second end of the burner tube for supplying fuel into a mixing zone arranged in the region of the second end of the burner tube;
• • A coaxially arranged in the burner tube swirl device with a swirl tube and therein swirl elements, which has a first flow cross-section which is bounded inside by the at least one fuel tube and the outside by the swirl tube, for supplying a first part-volume flow helically twisted combustion air into the downstream the swirling device arranged mixing zone; and
• At least one second flow cross-section arranged coaxially in the burner tube and bounded internally by the swirl tube or at least one overtube enclosing the swirl tube and externally by at least one over tube or the burner tube enclosing the swirl tube, to separate at least a second partial volume flow of combustion air the first partial volume flow of combustion air helically twisted in the swirl device into the mixing zone arranged downstream of the swirl device.

In embodiments which do not have the outer tube enclosing the swirl tube, the annular gap between the swirl tube and the burner tube forms a second flow cross section, through which a second partial volume flow of combustion air is conducted, but has not been actively influenced. In other embodiments, which additionally have a swirl tube enclosing the overtube, two second flow cross-sections, whereby the second part-volume flow of combustion air is divided again. In this case, one of the two second flow cross sections is bounded on the inside by the swirl tube and on the outside by an over tube surrounding the swirl tube and the other of the two second flow cross sections is bounded on the inside by the over tube and on the outside by the burner tube. Both second partial flow rates have not been actively influenced in known burner heads so far fluidically.

• • vor oder/und an oder/und hinter dem Eintritt in die stromabwärts der Dralleinrichtung befindliche Mischzone eine Wirbeleinrichtung mit mindestens einem Wirbelelement zur Verwirbelung mindestens eines zweiten Teil-Volumenstroms von Verbrennungsluft zumindest um eine quer zur Strömungsrichtung verlaufende Richtung angeordnet ist.

According to the invention, it is now proposed in such burner heads that

• A vortex device with at least one vortex element for vortexing at least a second partial volume flow of combustion air is arranged at least around a direction running transversely to the flow direction before and / or at and / or after entry into the mixing zone located downstream of the twisting device.

In other words, as before, within the burner tube, a first partial volume flow of combustion air introduced into the burner tube at the upstream first end should be "twisted", i. be placed in a helical flow around the central longitudinal axis of the burner tube.

In addition to this, at least a second partial volume flow, which until now has been left essentially untreated in terms of flow, should now also be "swirled". This swirling can take place at one or more positions in the area of at least one second flow cross section along the flow direction of the or a second partial volume flow. If, for example, the vortex device comprises three vortex elements, then for example a first vortex element can be arranged in the middle region of the second flow cross-section, viewed in the flow direction, a second vortex element in the region of the downstream end of the second flow cross-section, i. immediately before or after entry of the second partial volume flow into the mixing zone, and a third vortex element behind the second flow cross-section, i. within the non-combustion mixing zone.

For a clear distinction from the hitherto practiced "twisting" of the first partial volume flow, the term "vortexing" is introduced here for the proposed treatment of the at least one second partial volume flow of the combustion air, which in actual fact is something other means than the well-known "twisting" and should also be understood. What is meant by the term "swirling" used here is that in the flowing fluid, a vortex is generated, which at least also rotates about a direction transverse to the flow direction.

In known burner heads, the total volumetric flow of combustion air blown into the first, upstream end of the burner tube through the swirl device into a first partial volume flow, which is twisted in the first flow cross section of the swirl device, and a second partial volume flow between the swirl device and burner tube in the second flow cross-section fluidically largely uninfluenced the mixing zone supplied, divided.

In some advanced burner heads, the second partial flow in the direction of flow is divided again approximately in the middle of the swirling means, by an over-tube which encloses the swirling tube with a radial distance and, for example, approximately from the center of the swirling device to its downstream second end extends. The purpose of this over tube and the associated re-division of the second part volume flow into two second part volume flows is to influence certain speed and pressure conditions in the region of the downstream end of the burner tube, which affect the intake of recirculated exhaust gases.

When applying the improvement measures proposed here, at least one of these second partial volume flows should be swirled at least around a direction running transversely to the direction of flow, whereby the second part volume flow guided completely outside, between burner tube and over tube preferably swirls at least around a direction running transversely to the flow direction becomes.

With reference to the proposed burner head, this means that in embodiments which have an over-tube in addition to the swirl device, a swirl device is preferably arranged between the over-tube and the burner tube. Of course, however, a vortex device can alternatively or additionally be arranged between the vortex tube and the overtube without departing from the inventive concept.

The "swirling" of the at least one second partial volume flow can take place in different ways:

For example, it can be provided in the proposed burner head that the at least one vortex element comprises at least one second edge of the flow reducing, concentric with the burner tube arranged vortex edge. Such a vortex edge may, for example, be a boundary of a ring serving as a vortex element, which is arranged at the inner or outer diameter of the second flow cross section or in the middle of the second flow cross section, embodiments of the invention are included, in which the vortex device combinations of two or more such Include vertebral elements. The flow lines of the flowing fluid impinging on such a ring, i. of the at least one second partial volume flow of the combustion air, are braked and then forced to flow around the vortex element. The greater the flow resistance of the vortex element, the greater the resulting turbulence, which in turn depends on its cross-sectional shape (i.e., the sectional area of the vortex element which becomes visible in a longitudinal section through the burner tube).

According to one embodiment, it can be provided that the vortex edge is continuous, for example circular, in the direction of flow. As a result, a relatively uniform turbulence of the at least one second partial volume flow of the combustion air is achieved, which nevertheless subsequently achieves a significantly better mixing of the combustion air with the fuel and possibly recirculated exhaust gas, because the twisted first part volume flow and the swirled at least one second part Volumetric flow meet and achieve a much more homogeneous mixing than was known from the prior art.

According to one embodiment it can be provided that the vortex edge is discontinuous, for example toothed. Such serrations of a vortex edge of a vortex element can be based, for example, on the basic shape of a triangular function, rectangular function, trapezoidal function, etc., which, however, extends circumferentially through the basically annular second flow cross section and is therefore infinite.

As already stated above, it can be provided, for example, that at least one swirl element is attached to the outside of the swirl tube or over tube, and / or that at least one swirl element is attached to the inside of the burner tube, or / and that at least one swirl element is interposed between the swirl element Inside the burner tube and the outside of the Twist tube or overtube, ie in the middle of the second flow cross-section, is mounted.

It has been found that with the proposed improved burner head in comparison with known burner heads simultaneously with a stabilization of the flame a significant reduction of pollutant emissions, in particular the emission of soot, carbon monoxide and nitrogen oxides, by homogenization of the fuel combustion air mixture and consequent the degradation of temperature peaks, could be achieved. In other words, the arrangement of a vortex device in the second flow cross-section, taken by itself, represents a nitrogen oxide-reducing measure; however, it also allows further nitrogen oxide reducing measures, as described below:

The swirl means may be located axially within the burner tube relative thereto. along the flow direction, slidable to set certain fluidic process parameters that affect the stability of the flame and the exhaust emissions, so that an optimal operating point can be found.

In accordance with a further embodiment, provision can moreover be made for the vortex device to be displaceable as a whole and / or for at least one of a plurality of vortex elements of the vortex device to be axially displaceable relative to the twisting device. In other words, embodiments of the inventive concept are also encompassed in which an arrangement of a plurality of swirl elements is displaceable relative to the swirl device or a swirl element of the swirl device is displaceable relative to other swirl elements of the swirl device and relative to the swirl device or several swirl elements of the swirl device are independent relative to each other Whirl elements of the vortex device and relative to the swirl device are displaceable. As in the case of an axially displaceable swirl device, and also in combination with an axially displaceable swirl device, thereby fluidic process parameters that affect the stability of the flame and the exhaust emissions can be selectively changed and adapted to specific conditions of use.

The proposed solution is technically simple, inexpensive to produce and it is suitable to retrofit in the context of retrofit measures quickly, easily and inexpensively in existing burner heads by subsequently a vortex device of the type described is attached.

• • Zuführen von Verbrennungsluft und unverbranntem Brennstoff in eine verbrennungsfreie Mischzone, die im Bereich eines stromabwärtigen Endes des Brennerkopfs vorgesehen ist, um ein zündfähiges Brennstoff-Verbrennungsluft-Gemisch zu erzeugen;
• • Zuführen des Brennstoff-Verbrennungsluft-Gemischs in die Verbrennungszone; und
• • Verbrennen des Brennstoff-Verbrennungsluft-Gemisches in der Verbrennungszone;
• • wobei vor dem Zuführen von Verbrennungsluft in die verbrennungsfreie Mischzone mindestens ein erster Teil-Volumenstrom von Verbrennungsluft verdrallt wird;
• • zusätzlich zu dem ersten Teil-Volumenstrom von verdrallter Verbrennungsluft und getrennt von diesem mindestens ein zweiter Teil-Volumenstrom von

With the proposed improved burner head, an improved method of combusting fuel in a combustor downstream combustion zone provided in a combustion chamber that enables stable combustion and power output and low emissions of pollutants can be realized. The proposed method has the following steps:

• Supplying combustion air and unburned fuel into a combustion-free mixing zone provided in the region of a downstream end of the burner head to produce an ignitable fuel-combustion air mixture;
• Feeding the fuel-combustion air mixture into the combustion zone; and
• Burning the fuel-combustion air mixture in the combustion zone;
• Wherein, before supplying combustion air into the combustion-free mixing zone, at least a first partial volume flow of combustion air is twisted;
• • In addition to the first part volume flow of twisted combustion air and separated from this at least a second partial flow of

• • mindestens ein zweiter Teil-Volumenstrom von Verbrennungsluft vor oder/und bei oder/und nach dem Zuführen in die verbrennungsfreie Mischzone zumindest um eine quer zur Strömungsrichtung verlaufende Richtung verwirbelt wird.

Combustion air is fed into the combustion-free mixing zone; and

• • At least a second partial volume flow of combustion air before and / or at and / or after feeding into the combustion-free mixing zone is swirled at least by a direction transverse to the flow direction.

In other words, depending on the specific conditions of use, the method can be designed such that the turbulence of the at least one second partial volume flow takes place within a second flow cross-section or at the end thereof, i. the transition to the combustion-free mixing zone, or within the non-combustion mixing zone. On the device side, this can be realized, for example, in that at least one vortex element is arranged within the combustion-free mixing zone or can be moved into it.

In a further embodiment of the proposed method, it can be provided that the at least one second partial volume flow of combustion air is substantially toroidally swirled, i. that forms behind the at least one vortex element, a toroidal vortex. A torus is a geometric object that has the shape of a lifebuoy, hoop, or donut.

An essentially toroidal swirling can be achieved, for example, by arranging a swirling device with at least one swirl element at the transition from the swirling device to the mixing zone, ie at the respective downstream end of the first flow cross section and the second flow cross section, on or in the second flow cross section has a smooth, ie continuous, for example, circular, elliptical or similar vortex edge.

For example, the vortex element may be a simple sheet-metal ring, ie a ring with a rectangular cross-section, which is fastened to the outside of the swirl tube and protrudes a few millimeters into the second flow cross-section. This can be in the context of a retrofit solution, for example, a separate part, which has at its inner ring diameter tabs with holes, by means of which the ring is screwed to the swirl tube. A toroidal flow is formed in the second part volume flow immediately behind the sheet metal ring, which then mixes with the helical flow of the first part volume flow.

Alternatively or additionally, it can be provided in the proposed method that the at least one second partial volume flow of combustion air is substantially so swirled that it forms a Karman vortex street on entering the combustion-free mixing zone. A Kärmän vortex street is a phenomenon in fluid mechanics in which opposing vortices form behind a body that flows around it. The character of vortex formation is essentially determined by the Reynolds number Re. It represents the ratio of inertia to toughness forces and is calculated from the flow rate, the diameter of the body and the viscosity. In the simplest case, that of a fixed cylinder in a stationary flow, different configurations of the vortex street can be observed on the basis of the Reynolds number: At very low speeds, no flow separation takes place at all. With increasing speed, two counter-rotating vortex bubbles form on the downstream side, which become increasingly unstable and then begin to show a typical, periodic pendulum motion.

• 1 ein erstes Ausführungsbeispiel eines verbesserten Brennerkopfes im Längsschnitt,
• 2 ein zweites Ausführungsbeispiel eines verbesserten Brennerkopfes im Längsschnitt,
• 3 ein drittes Ausführungsbeispiel eines verbesserten Brennerkopfes im Längsschnitt, und
• 4 ein viertes Ausführungsbeispiel eines verbesserten Brennerkopfes im Längsschnitt.

The invention will be explained in more detail with reference to embodiments and accompanying drawings. Show

• 1 a first embodiment of an improved burner head in longitudinal section,
• 2 A second embodiment of an improved burner head in longitudinal section,
• 3 a third embodiment of an improved burner head in longitudinal section, and
• 4 A fourth embodiment of an improved burner head in longitudinal section.

The embodiments illustrated in the figures are all based on the embodiment according to 2 of the patent EP 2 037 173 B1 However, it should not be construed that the invention would be applicable to this particular embodiment only. Rather, the proposed solution can be used to improve all previously known burner heads, especially those that use the free flame technology, in which the flame is thus formed downstream of the burner head, and in which the combustion air in at least two partial flow streams of or one of several Mixing zones is supplied, wherein a first part-volume flow is twisted helically.

Because of the explanation of features of the patent EP 2 037 173 B1 taken embodiment, which are not relevant to the present invention and therefore are not described separately herein, reference is made to the statements there.

The illustrated burner head is designed as a dual fuel burner with which liquid and gaseous fuels (e.g., oil, gas) can be burned. It should be noted, however, that the solution according to the invention can be used advantageously not only for dual-fuel burners, but of course also for single-fuel burners.

The burner head is going outward from a burner tube 1 limited, which is an upstream, open first end 11 for feeding combustion air into the burner tube 1 and a downstream, open second end 12 for delivering an ignitable mixture of fuel and combustion air. The second end 12 is designed to dispense a fuel-combustion air mixture previously in a mixing zone within the burner tube 1 is formed by mixing fuel and combustion air.

About a first fuel connection 21 liquid fuel can be supplied via a first fuel tube 2 one in the area of the second end 12 of the combustion tube 1 arranged first fuel nozzle 22 can be supplied, which for liquid fuel is designed and can deliver such under pressure. The first fuel pipe 2 is central and coaxial in the burner tube 1 arranged.

Via a second fuel connection 31 it is possible to supply gaseous fuel which flows via a second fuel tube 3 several in the area of the second end 12 of the combustion tube 1 arranged fuel nozzles 32 can be supplied, which are designed for gaseous fuel. The second fuel pipe 3 is also central and coaxial in the burner tube 1 arranged. Because the second fuel pipe 3 has a larger diameter than the first fuel tube 2 , is the first fuel pipe 2 inside the second fuel tube 3 arranged and enclosed by this.

On the outside of the second fuel tube 3 is a twisting device 4 arranged, which is a swirl tube 41 as well as in the swirl tube 41 arranged swirl elements 42 includes a first part flow rate at the first end 11 of the burner tube 1 introduced combustion air in a helical twisted flow. The between the outside of the second fuel tube 3 and the inside of the swirl tube 41 , central and coaxial in the burner tube 1 is arranged and the second fuel pipe 3 encloses, formed annular gap forms for this purpose a first flow cross-section.

The outside of the swirl tube 41 between the outside of the swirl tube 41 and the inside of the burner tube 1 formed annular gap forms a second flow cross section, through which a second part-volume flow at the first end of the burner tube 1 Initiated combustion air - initially largely unaffected - flows.

At the end of the swirl tube 41 closes downstream of a mixing zone, in which the two part-volume flows of the combustion air are brought together and mixed with each other after flowing through the first flow cross-section and the second flow cross-section. In addition, the thus blended combustion air is mixed with the fuel (s) emanating from the first fuel nozzle 22 and / or the second fuel nozzles 32.

Subsequently, the thus formed fuel combustion air mixture at the second end occurs 12 of the burner tube 1 through the guide devices arranged there 13 , which extend from an end face arranged annular aperture, the so-called Deltablende obliquely into the Ausströmquerschnitt out of the burner head, so that can form a flame with the downstream distance in front of the burner head. The combustion-free mixing zone, in which the ignitable fuel combustion air mixture is generated, thereby extends approximately from the end of the swirl device 4 to the downstream end of the baffles 13 and possibly beyond.

At the downstream end of the second flow cross section, ie in the region of the transition from the second flow cross section into the mixing zone, there is a vortex device 5 with at least one vortex element 51 arranged in the second flow cross-section. This vortex device 5 , one or more, possibly differently designed and mounted at different locations vortex elements 51 At least also around a direction transverse to the flow direction, turbulent flow of the second partial volume flow of the combustion air, which subsequently into the downstream of the swirl means, generates swirling flow 4 arranged mixing zone enters and mixed with the second, twisted part volume flow of the combustion air and the fuel.

In the first embodiment according to 1 is a vortex element 51 in the form of a sheet metal ring on the outside of the swirl tube 41 attached, the one the second flow cross-section, concentric with the burner tube 1 arranged vortex edge 52 includes, wherein the vortex edge 52 is continuous, more precisely circular. The inner, the swirl tube 41 Near-stream lines of the second part-volume flow of the combustion air need this vortex edge 52 flow around, leaving behind the vortex element 51 forming a toroidal (donut-shaped) vortex ring.

2 shows a second embodiment in which a vortex element 51 between the inside of the burner tube 1 and the outside of the swirl tube 41 is appropriate. This can for example by (not shown here) rod-shaped spacers extending in the radial direction either from the burner tube 1 or from the twisting device 4 to the vortex element 51 extend, be realized. The vortex element 51 itself has a circular cross-section and thus no pronounced vortex edge, resulting behind the vortex element 51 forming a Karmän vortex street.

In the third embodiment according to 3 is a vortex element 51 in the form of a sheet metal ring on the inside of the burner tube 1 attached, the one the second flow cross-section, concentric with the burner tube 1 arranged vortex edge 52 includes, wherein the vortex edge 52 discontinuous, more precisely toothed is formed, which is behind the vortex element 51 forms a disordered vortex ring.

This in 4 illustrated fourth embodiment shows a burner head, in which on the outside of the swirl tube 41 along the downstream half of an over tube 43 with inlet openings 44 is arranged, the second part volume flow approximately in the middle of the swirl tube 41 divided into two second partial flow rates. The inner of these two second flow cross sections is through the between the swirl tube 41 and the overtube 43 existing annular gap formed and the outer of these two second flow cross sections is through the between the overtube 43 and the burner tube 1 existing annular gap formed.

In this embodiment, the vortex device comprises 5 two vortex elements 51 , A first vortex element 51 is on the inside of the over tube 43 that is, disposed at the outer diameter of the inner second flow cross-section at the downstream end thereof. A second vortex element 51 is on the outside of the over tube 43 , that is, disposed at the inner diameter of the outer second flow cross section, also at its downstream end.

LIST OF REFERENCE NUMBERS

1

burner tube

11

first end

12

second end

13

guide

14

Delta panel

2

first fuel pipe

21

first fuel connection

22

first fuel nozzle

3

second fuel pipe

31

second fuel connection

32

second fuel nozzle

4

swirl device

41

twisted tube

42

swirl element

43

About pipe

44

inlet port

5

swirler

51

vertebral element

52

swirl edge

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19509219 A1 [0003]
• EP 1245901 A1 [0004]
• DE 19704721 A1 [0004]
• DE 102005038662 A1 [0004]
• EP 2037173 B1 [0006, 0007, 0008, 0038, 0039]

Claims (13)

A burner head for combusting fuel in a combustion zone downstream of the burner head, comprising: a burner tube (1) having an upstream first end (11) for feeding combustion air into the burner tube (1) and a downstream second end (12) for dispensing an ignitable mixture of fuel and combustion air; At least one fuel tube (2, 3) arranged coaxially in the burner tube (1) and having at least one fuel nozzle (22, 32) arranged in the region of the second end (12) of the burner tube (1), for supplying fuel to one in the region of second end (12) of the burner tube (1) arranged mixing zone; A swirling device (4) arranged coaxially in the burner tube (1), having a swirl tube (41) and swirl elements (42) arranged therein, which has a first flow cross-section which extends internally through the at least one fuel tube (2, 3) and through the outside Swirl tube (41) is limited, for supplying a first part-volume flow of helical twisted combustion air in the downstream of the swirl means (4) arranged mixing zone; and at least one second flow cross section arranged coaxially in the burner tube (1) and extending inside through the swirl tube (41) or at least one overtube (43) enclosing the swirl tube and externally by at least one over tube (43) enclosing the swirl tube or the burner tube (1 ) is limited, for guiding at least a second part-volume flow of combustion air separated from the in the swirl means (4) helically twisted first part volume flow of combustion air in the downstream of the swirl means (4) arranged mixing zone; characterized in that • before and / or at and / or behind the entry into the downstream of the swirl device (4) located mixing zone a vortex device (5) with at least one swirl element (51) for swirling at least a second part-volume flow of combustion air at least a direction transverse to the flow direction is arranged. Burner head after Claim 1 , characterized in that the at least one swirl element (51) at least one, the second flow cross-section reducing, concentric with the burner tube (1) arranged vortex edge (52). Burner head after Claim 2 , characterized in that the vortex edge (52) is continuous. Burner head after Claim 2 , characterized in that the vortex edge (52) is discontinuous. Burner head according to one of the preceding claims, characterized in that at least one swirl element (51) is attached to the outside of the swirl tube (41). Burner head according to one of the preceding claims, characterized in that at least one swirl element (51) is attached to the inside of the burner tube (1). Burner head according to one of the preceding claims, characterized in that at least one swirl element (51) between the inside of the burner tube (1) and the outside of the swirl tube (41) is mounted. Burner head according to one of the preceding claims, characterized in that the swirl device (4) is axially displaceable relative to the burner tube (1). Burner head according to one of the preceding claims, characterized in that the swirl device (5) and / or at least one of a plurality of swirl elements (51) of the swirl device (5) is axially displaceable relative to the swirl device (4). Burner head according to one of the preceding claims, characterized in that in a burner head according to the preamble of Claim 1 Subsequently, a vortex device (5) according to the characterizing part of one or more of Claims 1 to 9 is appropriate. A method of combusting fuel in a combustion zone located downstream of a burner head and provided in a combustion chamber, comprising the steps of: supplying combustion air and unburned fuel to a combustion-free mixing zone provided in the region of a downstream end of the burner head to produce an ignitable fuel To produce combustion air mixture; Feeding the fuel-combustion air mixture into the combustion zone; and • combusting the fuel-combustion air mixture in the combustion zone; Wherein, before supplying combustion air into the combustion-free mixing zone, at least a first partial volume flow of combustion air is twisted; and • in addition to the first part volumetric flow of displaced combustion air and separately therefrom, at least a second part volumetric flow of combustion air is fed into the combustion-free mixing zone; characterized in that • at least a second partial volume flow of combustion air before and / or at or / and after entering the combustion-free mixing zone is swirled at least by a direction transverse to the flow direction. Method according to Claim 11 , characterized in that the at least one second part-volume flow of combustion air is substantially toroidally swirled. Method according to Claim 11 or 12 , characterized in that the at least a second partial volume flow of combustion air is substantially fluidized so that it forms a Karman vortex street.

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